A recent development in display technology is the adding of ambient light effects using an ambient light illumination system to enhance the visual experience when watching content displayed on the display device. This ambient light effect illuminates the surroundings of the display device, such as a television, with light associated with the content of the image currently displayed on the display device. For example, the ambient light effect is generated using an ambient light system which is part of the display device. The illumination system may illuminate a wall behind the display device with light associated with the content of the image. Alternatively, the display device may be connected to a remotely located illumination system for remotely generating the light associated with the content of the image. When the display device displays a sequence of images, for example, a sequence of video frames being part of video content, the content of the images shown in the sequence generally change over time which results in the light associated with the sequence of images to also change over time.
Such a light projection system is disclosed in WO 2005/076602, which discloses means for background lighting at the back of a display apparatus. The means for background lighting comprise two illumination units being provided at the right-hand and left-hand of the display apparatus. The illumination units are formed as substantially vertically positioned longitudinal light guides comprising means for coupling out light. The light guides are provided on at least one of its ends with a light source. The light source preferably comprises colored LEDs.
A drawback of the known ambient light system is that the illumination of the surface is not homogeneous.